Compound for accelerating the vulcanization of caoutchouc



Patented .1... 26.1926.

um'rsoesrArss PATENT OFFICE.

VICTOR LEFEIBURE'AND -ANTHONY JAMES HAILWOOD, OF MANCHESTER, ENGLAND; ASSIGNQBS TO BRITISH DYESTUI'FS COBPQRATION LIMITED, 01 MANCHESTER,

LANCASHIRE, ENGLAND.

COMPOUND FOR ACCELEBATING THE'VULCANIZATION F CAOUTCHOUC.

No Drawing.

and ANTHONY J afMss HAILWOOD, subjects of the King of England, and residents of Mane I 5 chester, in the county of Lancashire, Eng-.

land, have invented certain new and useful Improvements ,in new Compounds for Accelerating the Vulcanization of Caoutchouc,

of which the following is a specification.

In Letters Patent No. 1,157,177 Stanley John Peachey described the process of accelerating the vulcanization of rubber by adding paranitrosodimethylaniline or one of its homologues to the rubber sulphur mix and subsequently heating. This invention has proved to be of very great importance and none of the bodies recommended either before or since for accelerating the vulcanization ofrubber appear to give such'good results in many respects as does paranitrosodimethylaniline or its equivalents. Its application sufi'ers, however, from the disadvantage that it is liable to stain the skin duringhandling of, the rubber mixture and further that some persons who ap arto be particularly susceptible to the action of nitrosodimethylaniline develop a rash whenv working with it.

We have discovered a new body produced by the interaction of one. molecular proportion of paranirosodimethylaniline with two fproportlons o B-naphthol, which can read- 11 be repared and'which afiords a means 0; .app lfying paran-itr'osodimethylaniline or an equlvalent body in the vulcaniaation process whilst substantially if not entirely avoiding the above disadvan-' 'tages. ,The'new p a not is a molecular compound and'evinces. the chemical properties of its components. It 13 usually a neuent invention it is not 11 that the in,- teraction between the two components be tral. 'gray color, varying somewhat with thecircumstances ofpreparation'. In the prescomplete; eflicient materials can be obtained Application filed October 1, 1923. Serial No; 666,031.

paste for safety; the new product can be applied, transported and stored as a finely divided powder. The new product While quite stable is a molecular compound, or compound of addition readily dissociatedinto its constituents. I

In pure rubber mixes the addition of ,B-naphthol appears to exert little or no ef-. feet on the rate of vulcanization, but the new compound of B-naphthol and paranitrosodimethylaniline has a distinctly greater effect than is accounted for y its content of paranitrosodimethylaniline.

The composition of the stable molecular compound of paranitrosodimethylaniline and ,Bnaphthol was ascertained by treating an aqueous solution of .nitrosodimethylaniline with B-naphthol. Upon adding one molecu-,

lar proportion of ,B-naphthol to the solution, about one-half of the nitrosodimethylaniline is removed and only when two molecular proportions of ,B-naphthol are added is substantially the whole of the nitrosodimethylaniline combined with ,B-naphthol and precipitated. Whilst this method of preparing the new body shows its composition, it is unnecessary to'use an aqueous solution for the preparation of the product, which can be obtained by grinding together the nitroso base and B-naphthol in the roportions of one molecule of. the nitros methylaniline body to two mol ecules of the ,B-naphthol when combination-takes placewith a small liberation of heat.

.Also it is not the compound of paranitrosodi'methylaniline and-.fl-naphthobbe prepared before the apiibsolutel'y necesary that I plication to the rubber for if the two bodies The naphthol compound made ble' to combine with the nitroso body yielding an indophenolic body, and although we recommend the use of the. molecular compound containing the nitroso body and the naphthol in the proportions of one'molecule 0 to two it isto be understoodthat a mixture of this body with more naphthol or with more nitroso body can be employed if desired.

The following example will illustrate the manufacture of our new product 150 parts of pure, finely divided paranitrosodimethylanlline are mixed at ordinary temperature with 288 parts of pure, finely divided ,B-naphthol. Combination begins immediately, with slight development of heat and is complete in 2-3 hours if the mixing is perfectly intimate. The combination is noticeably accelerated if the intimate mixture is ground in a mill which exerts a slight mechanical pressure on the powder, as is done, for example, in an ordinary mortar. The completion of the combination is shown by the cessation of heat-development and also by the complete homogeneity of the product when viewed microscopically. The powder thus obtained is ready for use.

Instead be used.

The new produc can be applied in the vulcanization of ru her as follows 90 parts of rubber are mixed on the rolls with 7 parts of sulphur, 5 parts zinc oxide of paranitrosodimethylaniline equivalent paranitrosodialkylarylamines can and 1 part of the new compound and after thoroughly mixing the mass is heated at 40 lbs. steam pressure for 20-30 minutes when the rubber will be found to be fully vulcanized, that is in less than one-third of the time required when an accelerator is not used.

We claim- 1. As a new product a stable molecular compound of one molecular proportion of paranitrosodialkyl-arylamine and two molecular proportions of B-naphthol.

2. As a new product a stable molecular compound of one molecular proportion of paranitrosodialkylaniline and two molecular proportions of the fi naphthol.

As a new product a stable molecular compound of one molecular proportion of paranitrosodilnethylaniline and two n1olecular proportions of B-naphthol.

, I. As a new product a stable molecular compound of one molecular proportion of paranitrosoalkyl-arylamine and two molecuar proportions of ,B-naphthol.

In testimony whereof, wehave hereunto aflixed our signatures.

VICTOR LEFEBURE. ANTHONY JAMES HAILWOOD. 

